A number of bus connectivity protocols, such as the local interconnect network (LIN) protocols, utilize bit error detection. To illustrate, the LIN protocols provide that each bus device reflects the signal from its transmit output to its receive input, where bit errors are detected by simultaneously sampling the signal and its reflected version and comparing the samples to confirm whether there is a match. If the samples do not match, a bit error is signaled.
This bit error detection scheme typically is sufficient when the data transmission rate (e.g., the baud rate) is within a specified range. However, in many instances it may be advantageous to operate a transmission rate higher than the specified range. At these higher transmission rates, the propagation delay between the signal at the transmitter and the reflected signal may be greater than the sampling period, thereby resulting in misleading bit errors using the sampling technique described above. Conventional systems often attempt to overcome this problem by disabling bit error detection when the data transmission rate is greater than a defined transmission threshold. However, these conventional systems require that the bus devices receive explicit notification that the data transmission rate is going to exceed the defined transmission threshold, usually by transmitting an additional bus transaction prior to the high-speed bus transaction or by requiring additional side signals to write a register at each bus device. The need for explicit notification of a high-speed bus transaction therefore slows down the effective bandwidth of the bus as additional signaling is required or adds additional complexity for purposes of the side signaling. Accordingly, an improved technique for disabling bit error detection at higher transmission rates would be advantageous.
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